Coal fired water tube boiler



Dec. 24, 1940. H. VAN TONGEREN 2,225,808

com.. FIRED WATER TUBE BOILER iled Nov. 5, 193s 2 sheets-sheet 1 /VVE/Y TOE. HERMAN/V05 VAN To/VGQE/V Dec. 24, 1940. H. VAN TONGEREN 2,225,803

com. FIRED WATER 'TUBE BoILER Filed No'v. 5,"1938 2 Sheets-sheet 2 Patented Dec. 24, 1940 PATENT OFFICE 2,225,808 COAL FIREDWATER TUBE BOILER Hermannus van Tongeren, Heemstede, Netherlands Application November 5, 193s, serial No. .239,099 In Germany December Z4, 1937 11 Claims.

l" y water tube boilers of modem design have very spacious and high combustion chambers with a View to obtaining a more or less complete combustion of flue coke and to allow a maximum amount of lcoalto be burnt per unit grate area. It has also been suggested for the combustion chamber to taper upwardly, but until now it has been impossible in coal fired boilers to develop as much heat per unit combustion chamber volume as in oil fired boilers. Moreover, the greater the amountrof coal burnt per unit grate area, the greater the amount of flue coke carried along by the combustion gases. Said coke is partly deposited on the water tubes of the boiler, whereby the steam generation is seriously impaired, especially if it is impossible for the coke to be blown oil from said tubes by means of a steam jet or equivalent means. Finally, the water tubes are subjected to wear and tear by the erosive effect of the liuc coke particles.

The object of my present invention is to separate the flue coke, as far as possible, from the hot gases by which it is carried along, before these gases, on their way to the chimney, pass through the bundles of steam generating water tubes. The flue coke, which is thus prevented from eroding the water tubes and from interfering with the heat transmission, can be collected in any suitable manner and, if so desired, burnt on the grate.

With this object in view, my invention consists in the provision of a flue communicating with the combustion chamber and tapering in the maindrection of flow of the combustion gases, at least one lateral wall of said ue being composed of suitably spaced water tubes disposed transversely to said direction, in Such a manner that the gases are adapted to escape through the gaps between said tubes, whereas the particles of flue coke carried along by the gases follow substantially straight paths so as to reach the narrow end of the tapering flue, where they are discharged, preferably onto the furnace grate.

Further objects and features of my invention will be apparent to those skilled in the art from the following detailed description with reference to the drawings, in which:

Fig. 1 is a vertical sectional elevation of a coal fired water tube boiler,

Fig. 2 is a fragmentary cross-sectional elevation, on an enlarged scale, of three pairs of water tubes interconnected so as to form vanes, and

Fig. 3 is a fragmentary cross-sectional elevation, on an enlarged scale, of the baille by which the tapering flue is isolated from the combustion chamber.

Fig. 4 illustrates part of a second embodiment of the invention, partly in side` elevation, partly in cross-section.

The travelling grate of the boiler shown in Fig. 1 is indicated lby I, the combustion chamber by 2. The front wall and the side walls of said chamber are lined with water tubes 3. The reference 4 indicates headers for supplying water to, and the reference 5 designates headers for discharging water and steam from said tubes.

The rear wall of the combustion chamber 2 is formed by a steep, forwardly sloping refractory baille wall 6 resting on parallel water tubes 8. The tubes 8, which are supported by horizontal, water-cooled elements l, are provided with longitudinal fins 8a (Fig. 3) so as to form a substantially impervious wall. The spaces between the baiile wall 6, the tubes 8 and the fins 8a are filled with asbestos 8b or the like.

Owing to the slope of its rear wall, the combustion chamber tapers upwardly. At its top, it communicates with a forwardly sloping flue 9, of which the baiile 6 forms the front wall. The rear wall of said flue is constituted by a great number of suitably spaced, transverse horizontal water tubes I0, and since the slope of said rear wall is steeper than that of the baiile wall 6, the flue 9 tapers downwardly.

The space rearward of the pervious wall formed by the spaced tubes IIJ accommodates bundles of steam generating and other water tubes I I and is in communication with the stack I5.

The lower end of the downwardly tapering flue 9 opens vertically above the travelling grate I and in tha vicinity of compressed air nozzles I2 passed through the rear wall IB of the boiler.

It will be understood that, owing to the upward taper of the combustion chamber 2, the hot gases generated by the combustion of coal on the grate I will enter the flue 9 at a high speed. Said gases carry along a. great number of particles of coke and other solid matter, and if they pass through the flue 9, they will escape through the gaps between the water tubes I0 and flow, through the bundles Il, towards the chimney I5. The particles of coke, however, tend to follow the downward movement, owing to their inertia, so that they reach, together with a relatively small amount of gases, the lower end of the flue and fallkonto the grate I. If necessary, compressed secondary air jets are introduced through the nozzles I2 to positively draw the solid particles from the flue 9 and throw them onto the grate.

Fig. 2 shows that the horizontal transverse water tubes I are arranged in two parallel, slightly spaced planes, and that each tube in the rear plane is interconnected to a tube in the front plane `by a pair of strips I3 welded to both tubes. In this manner, each pair of tubes I0, together with the strips I3, whereby they are communicated, forms a water cooled vane disposed at an acute angle to the direction 0f flow of the gases throughy the flue 9, so that the gases escape between said vanes in a direction substantially opposite to that of the main gasflow in the flue. V

I wish it to ybe understood that itis not strictly necessary, for the purposes of my present invention, to form vanes in the manner stated. Single, plain tubes, either or not provided with fins or ribs, also causethe gases flowing through the flue 9 to be sharply defiected when escaping through the gaps between the tubes.

The tubes of the .bundles II can be used partly for generating steam, and partly for superheating or, preheating purposes, as circumstances require. v Fig. 4 illustrates an arrangement, wherein the lower, narrow end of the tapering flue 9 is connected to a plurality of relatively wide tubes I4, one of lwhich only has been shown, and through which the flue coke and part of the combustion gases is yadapted to be delivered for use outside the Iboiler.

What I claim is:

' 1. A coal fired water tube boiler comprising a grate, means defining a combustion chamber above said grate, means defining a flue rdisposed rearwardly of said combustion chamber and having an outletat its bottom for dust laden gases, said combustion chamber and said flue being in communication with each other at their tops, the means defining the entire rear wall of said flue comprising substantially horizontally disposed members vertically spaced apart for escape therebetween of gases from said flue, and steam generating water tubes rearwardly of the rear wall of said fiue in the path of gases flowing from said flue through the said rear wall'thereof.

2. A coal fired Water tube boiler comprising a grate, means defining a combustion chamber above said grate, said combustion chamber decreasing in cross sectional area upwardly, means defining a flue disposed rearwardly of said combustion chamber and having an outlet at its bottom for dust laden gases, said combustion chamber and said fiue being in communication with each other at their tops, the means defining the entire Vrearwall of-said flue comprising substantially horizontally disposed members vertically spaced apart for escape therebetween of gases from said fiue, and steam generating water tubes rearwardly of the rear wall of said ue in the path of gases flowing from' said flue through the said rear wall thereof.

3. A coal red water tube boiler comprising a grate, means defining a combustion chamber above said grate, means defining a fiue disposed rearwardly of said combustion chamber, and having an outlet at its bottom for dust laden gases, saidflue decreasing in cross sectional area downwardly, said combustion chamber and said flue being in communication with each other at their tops, the means defining the entire rear wall of said iiue comprising substantially horizontally disposed members vertically spaced apart for escape therebetween of gases from said flue, and steam generating water tubes rearwardly of the rear wal1 of said flue in the path of gases flowing from said flue through the ksaid rear wall thereof.

4. A coal fired water tube boiler comprising a grate, means defining a combustion chamber above said grate, said combustion chamber decreasing in cross sectional area upwardly, means defining a flue disposed rearwardly of said combustion chamber and having an outlet at its bottom for dust laden gases, said flue decreasing in cross sectional area downwardly, said combustion chamber and said flue being in communication with each other at their ltops, the means defining the entire rear wall of said flue comprising substantially horizontally disposed members vertically spaced apart for escape therebetween of gases from said fiue, and steam generating water tubes rearwardly of the rear wall of said flue in the path of gases flowing from said fiue through the said rear wall thereof.

5. A coal fired water tube boiler comprising a grate, means defining a combustion chamber above said grate, means defining a fiue disposed rearwardly of said combustion chamber and having an outlet at its bottom for dust laden gases, said combustion chamber and said flue being in communication with each other at their tops, the means defining the entire rear wall of said nue comprising substantially horizontally disposed waterV tubes vertically spaced apart for escape therebetween of gases from said flue, and steam generating water tubes rearwardly of the rear wall of said flue in the path of gases flowing from said flue through the said rear wall thereof.

6. A coal fired boiler as set forth in claim 1 in which'the means defining the rear wall of the combustion chamber and the front wall of the flue comprises a water cooled partition.

'7. A coal fired boiler as set forth in claim 1 in which the outlet at the bottom of the flue discharges into the lower portion of the combustion chamber.

8. A coal fired boiler as set forth in claim 1 in which the outlet at the bottom of the flue discharges into the lowerk portion of the combustion chamber, and means for supply of air across said flue outlet into the combustion chamber.

9. A coal fired boiler as set forth in claim 1 in which the means defining the rear wall of the flue comprises a first series of substantially horizontally disposed water tubes vertically spaced apart and, therebehind, a second series of substantially horizontally disposed water tubes vertically spaced apart, and upwardly and rearwardly inclined gas defiecting connections be- .tween the tubes of said rst series and companion tubes of the second series.

1G. A coal fired water tube boiler comprising a grate, means defining a combustion chamber above said grate, means defining a flue having an inlet end in communication with said combustion chamber, said flue decreasing in cross sectional area from its inlet end toward its opposite end and having at its opposite end an outlet for dust laden gases, the means defining said fiue including water tubes forming an entire wall of said flue, said water tubes being disposed transversely to the direction of flow of gases passing through the flue from the combustion chamber and being spaced apart to provide openings therebetween for the escape of gases from the flue, and steam generating water tubes disposed in the path of flow of gases after they have passed between said flue Wall dening Water tubes.

11. A coal ired Water tube boiler comprising means defining a combustion chamber, means dening a iiue having an inlet end in communication with said combustion chamber, said flue decreasing in cross sectional area from its inlet end toward its opposite end, the means defining said flue including Water tubes forming an entire Wall of said ue, said Water tubes being disposed transversely to the direction of flow of gases passing through the fiue from the combustion chamber and being spaced apart to provide openings therebetween for the escape of gases from the ue, and steam generating Water tubes disposed in the path of gases after they have passed between the Water tubes defining said flue Wall.

' HERMANNUS VAN TONGEREN. 

